Today my mother announced she could see a grey amidst my hair.

Since I'm in my 40s and don't own a supernatural painting a la Dorian Gray, I believed her, and without any particular angst.

But then my sister came running, gleefully (she has many, even though she's younger), and after a minute she announced, sorrowfully, that she couldn't see any grey in my hair.

Both those women have dismal eyesight.

Who should I believe?